Encapsulation of electronic devices is a very significant part of modern semiconductor technology, including inorganic and organic active material devices. Recently, organic semiconductor-based devices have been under development for display, lighting, energy conversion, energy storage, switching and logic applications. Degradation or parameter change of these devices due to the impact of species from the external environment has been a significant concern for many of these applications. In particular, in devices where high excitation densities, or less stable chemical or electronic states are formed during operation or as a result of their operation, inherent processing or materials composition, there is a risk of accelerated interaction with species such as O2, H2O, or H2. These substances can be present in the atmosphere in which the device is manufactured or operated. In some cases, such as metal-insulator-metal type organic light-emitting diode devices, the devices contain materials unstable to reaction with H2O and O2 even in their non-operating states. This would include device materials such as Ca, Ba, Li and related compounds that are used to facilitate charge injection into semiconducting active materials with low carrier densities. Common techniques to fabricate devices based on these types of materials include fabricating the active device on glass in an inert environment, then covering the top of the device by attaching a metal can or a second glass plate with adhesive, also in an inert atmosphere. An example of the basic configuration is shown in FIG. 1, with a device 11 mounted on bottom glass substrate 12 and metal can or top glass cover 14 secured with an adhesive layer 16. The glass and metal of this typical design provides a near hermetic seal. To extend storage and product lifetime in these types of devices, small solid, relatively thick and rigid patches of getters or desiccants 17 are placed within the free volume 18 within the encapsulation. The term “getter” is used in this specification to include materials with gettering, desiccating or scavenging functions. In this case, the high diffusive mobility of gaseous species leaking into the package and the very strong affinity and high sticking coefficient of these species on the getter patch lead to effective removal of potentially detrimental species from throughout the entire volume within the packaged device. Examples of suppliers and materials for this include SAES Dryflex, Dynic, Sud Chemie and others. Typical getter or desiccant patches are 80 microns thick to 3000 microns or more thick. A problem with this conventional encapsulation structure and technique is that the finished display is rigid, heavy, bulky, fragile and can be relatively expensive. For semiconductor devices made on plastic substrates, new technologies have been developed to create transparent, flexible barriers. One example is a series of alternating thin layers of polymer and inorganic materials to create a thin, transparent oxygen and moisture barrier layer that can be applied directly to the device or on to any plastic substrate. Several examples of these polymer-inorganic layered LEP devices can be found in U.S. Pat. Nos. 6,268,695; 6,146,225; 5,734,225; and 6,635,989. Again, application of these encapsulation layers is conducted in some inert environment. Metal foil type encapsulation layers can also be effective, in certain implementations, for device encapsulation. However, due to the environmental sensitivity of some conventional device materials, encapsulation needs to take place in a controlled environment in conventional approaches.
Electrochemical devices, including light emitting electrochemical devices, can be formed without the use of reactive and low work function metals or with reduced activity or amounts of low work function materials. However, in operation these materials can still be somewhat sensitive to excess moisture, oxygen and hydrogen. For the formation of devices at low manufacturing cost, reduction of oxygen is of particular interest. Manufacturing in air is advantageous for reducing manufacturing line complexity and cost as well as increasing throughput. In some cases, it is possible to dry and remove moisture, as well as hydrogen, solvents or other impurities, from the air in the proximity of the manufacturing line. However, the removal of oxygen precludes direct human access to those parts of the equipment. It is therefore advantageous in a device manufacturing process to allow the presence of oxygen. However, oxygen sealed in the device after manufacture can shift operation parameters and cause accelerated degradation.